(I wrote this when rating the game but it's not showing, so I'll just copy it)
I never thought a generic mystery system could exist. I was wrong.
I've been playing TOTWSaM for most of its beta period, through I think 4 different iterations of the game. There have been changes, of course, but the core always remained the same. And that's because it works.
Jamis has found a way to dissect what makes a mystery a mystery, what kind of clues are there and how you can get them... All of it independently of the specific genre you might be playing. I've played mysteries regarding: a jedi trying to find what happened to an old contact decades ago in a remote planet, a normal dude in today's actuality wanting to know if his uncle's death was really natural or not (and why is there a ghost in the manor he just inherited?), a university student in a steampunk/post-post-apocaliptic world receiving a mystery letter from a secret organization...
Whatever mystery you have in mind you can play. TOTWSaM doesn't make any assumptions. You can play with characters and worlds you already know, or you can build it from scratch as the game progresses.
I usually like to change things up and after a game move on to a new system, but since TOTWSaM is not a system but a framework that acts as an add-on I feel confident in saying that it's going to be a regular presence in my games.
Happy gaming!